Study of the incorporation of iron-aluminous lateritic material in the burning rate of thermoset matrix composites

ABSTRACT

The composite materials are versatile and can be applied in different sectors depending on the required needs and their characteristics, in order to reconcile factors such as safety, environment, economy. Lateritic materials are present in a large part of the national territory and may exhibit high levels of iron and aluminum oxide and hydroxides, and may have a significant influence on the thermal properties of polymer composites. The material used in the work originated in Piriá ridge, located in the municipality of Vizeu, in the State of Pará. The work consisted of the characterization of this material and the preparation of composites using it as a filler in an isophthalic polyester matrix, which were tested through flammability tests. Analyses of laser granulometry, X-Ray fluorescence spectroscopy (XRF) and Fourier Transform Infrared (FTIR), Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) were performed. The composites were made by hand lay-up process in a closed mold, with compression of 2.7 tons for 20 minutes. The volumetric fractions used to manufacture the composites were 10, 20 and 30 % and the flammability tests were conducted according to ASTM D 635-03. As results, the material was composed of fine particles with a mean diameter of 23.5 μm, consisting of 61.13 % Fe₂O₃ and 18.63 % Al₂O₃, confirming the presence of these oxides characteristic bands at 3448 cm^-1 indicate the presence of trivalent cations of Al³⁺ or Fe³⁺. The calorimetric behavior of this material presented phase transformations in a temperature range suitable for flame retardance, with significant loss of mass from approximately 270 ºC. In the composites with 30 % of lateritic material, the flame propagation was reduced by 69.86 % in relation to the polyester matrix, which makes it possible to study its application in composites.

Keywords
Laterite; Iron; Aluminum; Characterization